The invention relates to a converter for converting a terminal voltage of a battery connected between an input terminal and a reference terminal into an output voltage across a load connected between an output terminal and said reference terminal, comprising switching means for controlling the value of the output voltage to the value of a reference voltage, and a control circuit for controlling the switching means.
Such a converter is known from the prior art. Controlling the value of the output voltage takes place by means of pulse width modulation and/or frequency modulation of the switching means.
A disadvantage of the known converter is that it is not provided with a simple and at the same time accurate indicator for supplying a signal indicating that the battery is almost empty.
The load may be, for example, a hearing aid. An accurate indicator for supplying a signal indicating that the battery is almost empty is highly desirable here because in the absence thereof either the hearing aid may fail in an uncontrolled manner (i.e. unexpectedly), or a battery which is not nearly empty yet is replaced.